There is a transmission system in which a host apparatus (master apparatus) is connected to plural electronic devices (slave devices) through a common data line and data is transmitted between the host apparatus and the plural electronic devices.
In such transmission system, generally, the host apparatus permits a specific electronic device to occupy a data line and then data transmission between the host apparatus and the electronic device (data transmission from the host apparatus to the electronic device or data transmission from the electronic device to the host apparatus) is executed. When the data transmission is completed, the host apparatus permits another electronic device to occupy the data line and then data transmission between the host apparatus and the electronic device is executed.
However, in the conventional transmission system in which plural electronic devices are connected to one host apparatus through the common data line (for example, data bus), while one electronic device is occupying the data line, data transmission between other electronic device and the host apparatus cannot be executed. The other electronic device is obliged to wait until the initial electronic device has finished processing (including data transmission) and then execute data transmission.
To solve the above-mentioned conventional problem, the present invention intends to provide a transmission system with quick response, wherein even while one electronic device is occupying a data line, data transmission between the other electronic device and the host apparatus can be performed as necessary and plural electronic devices are connected to one host apparatus through a common data line, a method for controlling the transmission system, and a host apparatus and electronic devices constituting the transmission system.